The invention relates to a method for production of a tubular body, in particular a tube for transporting abrasive materials.
Tubular bodies are essentially required to transport partially solid and liquid materials; the tubular bodies are designed in the form of rotationally symmetric tubes and are subject to increased stresses caused by the materials to be transported. Abrasive materials are frequently transported, for instance water with solid components; they can have sharp edges in individual cases. Rubber tubes are customarily used for the transport that are reinforced if applicable with a textile so that corresponding compression forces of more than 120 bar can be accommodated. The service lives of rubber tubes of this type are very limited, so there is a desire to use other materials.
The published application DE 34 21 364 A1 discloses a method for producing oblong, hollow bodies, especially tubes, using a rotating core. Four roller brackets are allocated to the core from which overlapping webs of a separating film are unwound from supply rollers, and a liquid material, a reaction mixture or a melt is applied to the separating film via several feeder heads. The liquid material is applied here while a textile web that serves as a reinforcement material is simultaneously worked in.
Further methods for producing tubular bodies are known from EP 0 036 184 A1 and EP 0 184 759 A1; a reaction is brought about between at least two liquid or pasty components via a feeder head, and there are provisions for a simultaneous addition of a thread as a reinforcement material.
The methods known in the prior art have the drawback in connection with this that the elastomer materials are directly wrapped with a reinforcement layer in the form of a thread or a textile, and this thread permeates the pasty, elastomer materials and penetrates right down to the lowermost layers close to the core. The reinforcement material is consequently not located in the central area of the tubular body to be produced, but instead is concentrated in the direct proximity of the inner diameter. Strength that is desired over the entire cross section is therefore not ensured when there is a commensurate wall thickness of the outer layers of the rotationally symmetric body.